Kirschner wires, pins or Schanz screws are often used in surgery and for a wide variety of applications. Such thin wires or screws are first attached to a bone or bone fragment at their distal end and then attached to an external fixator in accordance with their function. After being attached to the bone, wires are cut to their desired length.
Disadvantages of this technique include the fact that
                after being cut, the free end of the wire has a burr which may cause irritation to the adjacent soft tissue; and        use of such wires is limited by the fact that practically only force-locking connections to other parts, e.g., screw heads or other anchoring elements, may be used on the proximal end of the wire. However this is unfavorable for applications as compression screws.        
DE 94 90 219 to HOWMEDICA discloses, for example, a compression device comprising a longitudinal bone fixation element with an axially displaceable stopper that can be locked in the desired position. The shaft and the central bore in the stopper each have a non-round cross-sectional area, so that the stopper is also locked with regard to rotation about the longitudinal axis of the bone fixation element. One disadvantage of this known device is that the bone fixation element must be designed like a toothed rack, which means a complex manufacturing process and thus high costs.